| 摘要 |
PURPOSE:To enhance toughness of the piping joint by utilizing slurry having specified viscosity and molding it so that an SiC whisker is dispersed in an Si3N4 matrix nearly parallel to the outer surface to the two-dimensional random directions in the whole region of a piping joint and sintering this molded body. CONSTITUTION:Slurry having <=3.0 poise viscosity is obtained by kneading Si3N4 powder having, about 1mum particle diameter, 10wt.% SiC whisker having about 0.1-1mum diameter and about 5-100mum length therefor and also about 15wt.% sintering adjuvant such as Al2O3 together with water added with a dispersant. This slurry is introduced into a mold and thickened to obtain a green molded body having >=60% density. This is roasted at 1700 deg.C for 3 hours in the N2 atmosphere. Thereby a piping joint made of ceramics having >=90% relative density is obtained wherein an SiC whisker 6 is orientated and dispersed two-dimensionally at random in an Si3N4 matrix nearly parallel to the outer surface 2-2 in the whole region of the inner surface 2-1 and the outer surface 2-2 of a piping joint. Furthermore tension stress held on the outer surface is reduced and progress of a generated fine crack 8 is stopped. |
